PCSAT2 ANTENNA PHASING HYBRID ASSEMBLY INSTRUCTIONS 7 May 2003
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The Phasing Hybrid has two separate/independent circuits, one for VHF and
one for UHF. The UHF is actually a square with legs 4.5" long and the VHF
is all folded around over itself and has legs that are 13.3" long.
NOTE: None of the LANDS on the PCB are of any significance except the
SHIELD connection points and the CENTER conductor pads. These HYBRIDs are
totally implemented within the coax pieces and are not dependent on the
copper foil paths. All the rest of the copper lands are only "artwork" to
show where the coax cables are routed. The board only supports the cables.
The UHF HYBRID is easy to see as a square around the edge of the board and
consists of two single lengths of 50 ohm cable on the top and bottom and
then two parallel pairs of 75 ohm RG-179 on the two sides. The antennas
and transmitter coax cables attach at the four corners.
The VHF hybrid had to be folded over and around itself to fit. It
also consists of two runs of 50 ohm cable and two parallel pairs of
75 ohm RG-179 cable. All VHF runs are 13.3 inches long from the
points of attachment of the center conductor of the coax.
NOTE: ALthough L2 and L3 are shown on the bottom of the board, that
was only to make it easy to lay out the board using the 3 colors of
the PCB drawing software. It was intended that all coax in the
HYBRID would be on the top except for the one 50 ohm UHF section
that needs to be on the bottom to allow room for connections of the
pigtails to the center connection points.
Also, IGNORE all the lengths shown for L1 through L6. These were the
actual measurments of the length of the artwork as drawn. They
simply proved that there is enough room for the actual 13.3" lengths.
ASSEMBLY: Any rigid/tinned coax can be used. Or Flexible 50 ohm cable
can be used. Whatever the Technicial feels is easiest to work with.
We only had the bare copper rigid line and only the RG-179 for the
75 ohm sections. But the VELOCITY FACTOR of any coax used must be 66%.
Begin with the 6 straight UHF pieces (one goes on the bottom of the
board and is slightly bent to clear other attachment points. Next
add L4 and L5. Then L2 and L3. Finally add L1 and L6. This
completes the HYBRIDS. We won't attach the coax pigtails until the
final mounting location has been determined and all of the lengths
have been determined. Although the VHF RXB and VHF-ANTB are shown
on the bottom of the board, they may be attached on the top.
STAKING: Any of the square pads around the board may be used to
attach jumper wires to hold the coax lines flat and in line.
NOTE: The objective (and it is possible) is to arrange the lines
as shown so that in all cases, the heights of the crossover points
are only one-high. The crossover points are staggered so that
there is no place where they should bunch up. If so, force them
around to fit. The layouts for L1 through L6 are not exact but
do attempt to show where the crossovers work best.
Any Questions, call me.
Bob Bruninga
410-293-6417